Tips on remote debugging for filesystem code

[Julian Elischer]

On 2/9/17 8:40 pm, Aijaz Baig wrote:
> I was finally able to deploy a FreeBSD-Current VM on Bhyve but even 
> with that setup I face a similar issue
>
> For instance I put a breakpoint on 'ffs_read' and let the debugged 
> VM continue but the control is neither returned to (k)gdb nor does 
> the VM actually run. It appears hung.
are you sure it's not stopped at the breakpoint in ddb on the console?
>
> Is there something within the ffs/ufs code that I need to be aware 
> of that it doesn't facilitate this sort of debugging? Or is it 
> because Bhyve is being run on FreeBSD which is itself run on another 
> hypervisor? Will that affect this?
>
> On Mon, Aug 28, 2017 at 7:03 PM, Aijaz Baig <aijazbaig1 at gmail.com 
> <mailto:aijazbaig1 at gmail.com>> wrote:
>
>     HI Gary
>
>     Just checked that. Indeed that was the case. In addition I was
>     running FreeBSD on top of vmware hypervisor and had not allowed
>     hardware acceleration features pass through to the FreeBSD VM.
>     It is now working! Need to explore more on getting it to connect
>     to GDB
>
>     Perhaps you'll see a thread soon for it (Has anything worked
>     perfectly for the first time ever?? ;) )!
>
>     On Mon, Aug 28, 2017 at 6:56 PM, Gary Palmer
>     <gpalmer at freebsd.org <mailto:gpalmer at freebsd.org>> wrote:
>
>         On Mon, Aug 28, 2017 at 01:12:09PM +0530, Aijaz Baig wrote:
>         > Thanks a lot bakul. Will certain look into this
>         >
>         > Nevertheless I got hold of a PowerEdge 320 system which
>         DOES have a POPCNT
>         > instruction which shows support for V-x support via EPT
>         but I still get the
>         > same error there
>         >
>         > sh /usr/share/examples/bhyve/vmrun.sh -c 1 -m 2048M -t
>         tap0 -d guest.img -i
>         > -I FreeBSD-10.3-RELEASE-amd64-bootonly.iso fbsd10
>         > Launching virtual machine "fbsd10" ...
>         > vm_create: Device not configured
>         >
>         > dmesg:
>         > vmx_init: processor does not support VMX operation
>         >
>         > cat /var/run/dmesg.boot | grep -i popcnt
>         >
>         >
>         Features2=0xffba2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND,HV>
>         >
>         >
>         Features2=0xffba2203<SSE3,PCLMULQDQ,SSSE3,CX16,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND,HV>
>         >
>         > Any ideas?
>
>         Hi,
>
>         Check the BIOS for virtualisation or other related options. 
>         Some BIOSes have
>         the ability to turn those features off, even if the
>         processor normally
>         supports them
>
>         Regards,
>
>         Gary
>
>
>
>
>     -- 
>
>     Best Regards,
>     Aijaz Baig
>
>
>
>
> -- 
>
> Best Regards,
> Aijaz Baig